Electrical insulator



C. 0. HAR'RINGTON.

ELECTRICAL INSULATOR.

APPLICATION FILED APR. 8. 1920.

Patented Aug. 9, l1921.

. i'rFieii.

ELECTRICAL INSULAIOR.

Application led April 8, 1920.

WN i me@ T 0 all whom 25 may concern:

Be it known that I, CLINTON C. HARmNG- TON, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electrical Insulators, of which the following is a specication.

My invention relates to electrical insulators. Its prime object is to provide an insulator having peculiar strength and durability. A specific object is to provide an insulator device having such properties in situations where the parts to be insulated from each other have relative movement which gives rise to a grinding action. ther important objects are to provide an insulator of such construction that its several elements or parts may be easily and thoroughly treated to provide them with desirable insulating properties; which may be easily shaped for particular uses; which may be readily assembled for use; which in some forms may have a relatively small amount of insulating material while providing a high degree of durability and the desired degree of electrical resistance. Cther. objects and advantages will appear hereinafter.

In the accompanying drawings, which.

form a part of this specification Figures 1 to 15 inclusive are fragmentary vertical cross sections showing in enlarged form the thickness of insulator elements or devices according to my present invention, and Fig. 16 is a cross section of a railway rail, with fish plates and forms of lmy new insulating device operatively positioned between the plates respectively and the rail.

The plates, strips,`etc., of Figs. 1 to 15' may be of any desired length and width according to particular-uses, and of thickness also to a large eXten't,`although for such uses as the rail joint insulation shown the several parts respectively will be relatively thin.

In many situations where electrical resist `Speccaton of Letters Patent.

Patented Aug. 2, 1921.

SerialvNo. 372,345.

away'and causing it to fail. In the railway practice mentioned the track rails constitute electrical conductors for operating the block signals, it being necessary to insulate from each other sections of the track at intervals, all as is Well understood. The importance of a form of insulation at these rail joints which will be notably free from the effect of the abrasive or other disintegrating forces found under conditions of service is appaent, and I have chosen this application of my improved insulator for illustration herein as an important example of its advantageous use.

Referring further to the drawings, Fig. 1 shows an insulator unit comprising a nietallic part 20 having an electrical insulating coating 21 on one side surface thereof.

Fig. 2 shows a unit having a metallic plate 22 with an insulating coating 23' on both sides and around the edges thereof.

Fig. 3 shows a plurality of metallic plates 20 each having an insulating coating 21 on one side thereof. This figure shows three of the plates of Fig. 1 ment. y 1

Fig. l shows three of the plates of Fig. 2 in laminated arrangement.

In Fig. 5 there are three metallic plates 24 and insulating material 25 in sheet form between them. The insulation 25 is shown as extending beyond the plates partly for the purpose of clearness of illustration and partly to show a construction in which the electrical current or static charge is prevented from jumping around the ends of the insulation from one plate to the other, should the charge come upon one or both of the outside plates.

Fig. 6 shows a plurality of the units of Fig. 2 with insulation material 25 in sheet form between the contiguous units 22-23.

In Fig. 7 there are two oppositely disposed elements 27 which it is desired to insulate from each other, with the unit of Fig. 2 between them.

Fig. 8 shows an insulator unit comprising a strong foraminous reinforcing element 2S, which may be wire mesh, and is so shown, with insulating material 29 embedding the mesh.

F 9 shows a similar construction to that of Fig. 8, but the inner member 30 is to be considered as of textile fabric, such as canvas for instance, with the insulating terial 31 laid upon the sides of the fabric.I

in laminated arrangethe surfaces of the metallic strips, sheets,

For coating the fabric it may be dipped into liquid insulating material and allowed v or caused to harden. i

Fig. 10 shows two of the units of Fig. 8 or Fig. 9 on opposite sides of a smooth metallic plate 872,. and upon these insulating units respectively are placed the members 33 which it is desired to insulate from each other.

In Fig. 11 there is a smooth metallic plate 35 and on its opposite sides is placed insulatingmater-ial 36 in sheet form, which may be considered as -ofiiber,celluloid, mica, etc., and on the outer `sides respectively of the parts 36`there are the members 37 to be iiisulated from each other.

In- Fig. 12 the parts 38 which it is desired to'insulatefrom each other are shown as having a serrated or lroughened surface facing insulation material 21 vupon the plates 20, Ithisfigure show-ing two of the units of Fig. 1. The plates 20 are smooth on their -surfaces facing each other and will slide upon each other when relative movement Voccurs between the parts 38. Y

In Fig.- 13 there are -two smooth plates 39 with insulating material 40 ybetween them, the wear or service plates 41 being next to the smooth plates `39 so as to slide'upon them.

In 'F ig. 14 `the service plate 42 lies lupon a smooth plate 48 which lies upon insulating material '44 which is next to two smooth plates 45 followed by an insulating element 46, which is succeeded by a smooth plate 47, this .being 'followed by insulation 48, and finally there is the opposite'plate lor service element 49V. The plate 42 mayV slide upon the plate 43 and the plates 45 may also slide upon each other, andthe insulating material may also slide upon the adjacent plates.

InFig. 15 thereis a service plate 50, insulation '51, three smooth plates 52, another insulating element 53, another smooth plate 54 and finally the other service plate 55. v

The electrical insulationl material which constitutes the coating on one or more` of plates or elements may be vany of the well known insulating materials available fer4 coating ymetallic parts such, for instance as varnish, enamels, japan, shellac, glazesyas well as other substances which mayfroin time to time ybe found available for such purposes. rlhe coating may also be vsuch asis produced by.chemical action in which thel surface of the metallic elements is :transformed, `for'instance by the formation ,of an loirid or other chemical compo-und having the property of electrical resistance, or, electrolytically, by depositing a surface coating upon the metallic partf The ,invention is not limited to any'sparticular kind of insul lating covering or coating upon the metallic parts.

By the terni electrical insulation in sheet form I mean such `,materials as mica, celluloid and the like, varnished or otherwise coated .textile or other fabric, fiber, paper, rubber, etc., having in mind all materials and substances in sheet form which in particular applications may be foundsuitable.`

A large variety o'f these is well known.

In Fig. 16 the rail 60, iisldlaplates 61and 62,' the bolt 63 and the insulating tube or bush character of the foundation Afor the rails andY to the wave-like motion of the rails under Y the vheavy rolling stock, and due to the sud-` den shifting of the load from one rail :to the other at therail joint, vthe Vtwo rails have 'relative movement between the 'ii-sh plates and the rails. The rail Vand the fish plates have comparatively rough surfaces where they face each other,7owing to the methods Vof construction employed, and where, according Ito prior practice, sheetform insulation is placed directly :between these elements it is soon worn away.-

v The' insulation 65 of Fig. 16 is to be considered as Vin laccordance withl Fig. 12 in which the outer members 38 may be Aconsidered the equivalent of the rail and fish plate y respectively, the insulationv device consist# ing of two of the plates of Fig. 1, these plates being smooth on their sides facing each other and being'adapted to slide upon each other when the fish plate and' rail move f relative to each other.V The insulation 661 of Fig. 16 may be considered to be in accordancev with vFig. 13 ofthe drawings? in which the wear plates 41 may be considered the equivalent of the rail 60 and thefish plate 62, there being a smooth plate adjacent be used where a' metallic elementl is part of the insulator device. Various other combinations -of the laminte may alsol be adopted.

The relative movement ofthe :fish plates Yiio and rail is relatively slight where the bolts f are suitably tightened, butV itis persistent, and the tendency to rgrind may t'alreplace over most of the surface of the insulation. In some cases the wear is limited chiefly to particular localities, and, accordingl to the present improvements where a .plurality of insulating media are employed, whilev the wear may in time destroy vone ofy the lmedia so'tliat metallic parts will be there rubbing together, other media will be left'intact andv the effectiveness of the insulation be thus preserved.

The smooth platesreferred to herein may be fairly thin, such as ordinary tin plate or copper sheet material of say 18 to 24C gage. In coating these plates they may conveniently be dipped in the soft insulating material and then either baked or hardened in the air according tothe character of material employed.

Some well known insulation materialsl suitable for such purpose do not crack or break when the metal to which they are applied is bent even at sharp angles. My improved form of insulator device may therefore have its several parts cut to the desired length and width, the parts laid upon each other in laminated form and by pressingthem in a die the entire device may be given its desired shape, as for instance that of the insulators 65 and 66 of Fig. 16.

An important advantage of the laminated construction employing relatively thin plates is in the flexibility which it gives the device as a whole in situations of relative movement between the parts to be insulated from each other. Thus when strains occur tending to bend the insulation as a whole the thin laminations slide upon each other and adjust themselves to the bent condition without breaking, each lamina bending individually as a unit; and, where the insulating material has a smooth surface to slide upon the wear is very slight, making for long life in service.

Another important advantage is that relatively thin sheets of paper, fabric, etc., may be more thoroughly impregnated with insulating compounds than is possible with the thicker sheets customarily employeld, rendering them less likely to absorb moisture and consequently reducing swelling and softening of the sheets. Insulation so formed is also less compressible, and this coupled with its merely slight expansion due to moisture eliminates in large part the trouble experienced with fiber insulation, which swells due to the absorption of moisture and on shrinking leaves the joint loose, thereby greatly increasing the Wear due to increased relative movement of the several parts at the joint.

A further feature of advantageous construction is to dip some or all of the laminas in melted paraffin `or -thelike, either before or after the laminas of the insulator device are assembled. Such a substance not only aids in water-proofing the device and its elements but, importantly, it acts as a lubricant between the laminas inducing more ready slippage. In the drawings insulators 65 and 66 are to be considered as having the several laminas so treated.

While I have referred herein to the plates 20, 22, 32, etc., as metallic the invention is not limited to metal in this respect, as, in some applications such substantially hard and smooth materials as hard pressboard,

Celluloid, etc., may be used. Various other changes may be made without departing from the spirit of my invention, and I contemplate all such departures as fall Within the scope of the appended claims.

I claim:

1. The combination with a pair of oppositely disposed members to be insulated from each other and having movement with respect to each other, of an insulator device between said members comprising a metallic element having a smooth surface on which a facing and contiguous member may freely slide and a layer of insulating material facing and contiguous to said metallic element.

2. The combination with a pair of oppositely disposed members to be insulated from each other and having movement with respect to each other, of an insulator device between said members comprising a thin metalic sheet having la smooth surface on each side thereof and insulating material contacting said surfaces and adapted to slide thereon. 4.

3. The combination with a pair of oppositely disposed members to be insulated from each other and having movement with respect to each other, of an insulator device between said members comprising a plurality of smooth metallic plates some of which contact and are adapted to slide upon each other, and insulating material between said pair of oppositely disposed members.

4. An electrical insulator device comprising a pair of oppositely disposed metallic elements, their facing surfaces being rough and adapted to hold insulating material firmly, a smooth metallic element between said other metallic elements, and insulating material between said smooth plate and said rough-surfaced elements respectively.

5. A laminated electrical insulator device comprising insulating material and a smoothly surfaced sheet on which the insulating material may slide.

6. The' combination with parts to be insulated from each other and having relative movement with respect to each other of an electrical insulator device comprising laminae free to slide one upon another.

7. In combination, a rail, a iish plate or the like at one side thereof, and between` the fish plate and the rail an insulating device comprising laminae free to move one upon another, and means for` holding the rail, insulator and fish plate together.

8. In combination, a rail, a sh plate, and between them an insulating device comprising laminas, one thereof being insulating material, another thereof being a hard and smooth-surfaced element adapted for slippage action relative to a facing contiguous member, and means for holding the fish plate, insulator and rail together.

9. In combination, a rail, a fish plate or ing metallic, the contiguouslaminee beingv free to move --upon each otherand means for holdingthe fish plate, insulator and -raifl together. 10. In combination, a rail, 4a `lishrgplatej,`

and between vthem an insulator device comprising insulating material and substantially hard and smooth slippage elements in alternate arrangement, and means for holding the fish plate, insulator and rail together.

11. In combination, a rail, arlish plate, and between'them a laminatedcinsulator device including substantially smooth and hard elements `adapted to slide one upon another, and l,means for holding Ithe fish plate, insulator yand rail together. l

12. In combination, a rail, a lish plate, and between them van insulator device com- 13. An electrical insulator devicecomprising' ametallic ,plate having a Aroughened surace,insulating material in sheet form facing..

and contiguous `tosaid surface, and a relatively thin and smooth metallic 1platefacing androntiguous to saidv insulating material, rthe smoothness of said plate being adapted to promote slippage between it and the in.

sulation. Y l I 14. In combination, va rail, a fish plate, and .between them Van insulator comprising laminee,}0ne of the lamineebeing coated Vwith a substance having the property of Vpromoting .slippage ,between the laminae.

v CLINTON 0.5HARVRIlIGrTGN. p 

